ALMA Chemical Evolution (ACE) survey: The gas fundamental metallicity relation at cosmic noon
Year: 2026
Type: preprint
Abstract: Chemical enrichment shapes how galaxies form and evolve. The gas-phase metallicity is directly linked to the stellar mass, star formation rate, and cold gas of the interstellar medium. Thus, the cold gas fundamental metallicity relation (GFMR) is a powerful tool for probing galaxy evolution, bridging large-scale gas flows modulating the cold gas reservoir and small-scale metal enrichment tracing the cumulative impact of star formation. Constraining all these properties for the same representative sample of galaxies remains challenging yet essential. Using CO(3--2) band 3 observations from the Atacama Large Millimeter/submillimeter Array Chemical Evolution (ACE) survey, we investigated the GFMR in a sample of 26 main-sequence (log(M_*, med)=9.96), subsolar-metallicity (12+log(O/H)_med=8.44) star-forming galaxies (SFGs) at z~2. With 17/26 CO detections, including some of the lowest-metallicity CO detections at cosmic noon, we find that the stellar mass remains the primary driver of the chemical evolution in our sample (sigmaMZR~0.10). Whereas the molecular gas likely plays a secondary role (sigmaGFMR~0.11) similar to that of the star formation rate (sigmaFMR~0.13). This likely reflects our sensitivity to only the CO-bright component of the molecular reservoir. Our results remain consistent with gas-regulator models and suggest the existence of efficient molecular outflows, with an average mass loading factor of eta~4, regulating star formation and chemical enrichment.
Source: arXiv (Cornell University)
Institutions: European Southern Observatory, Leiden University, Leiden Observatory, Australian National University, University of Massachusetts Amherst, University of Copenhagen, University of Florida, DTU Space, Technical University of Denmark, University of California, Riverside, University of Kentucky
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, Comunidad de Madrid, European Commission, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Korea Astronomy and Space Science Institute, Ministerio de Ciencia e Innovación, National Institutes of Natural Sciences, European Regional Development Fund, Agencia Estatal de Investigación
OpenAlex ID: W7213942257